Diagnosis of malignant granular cell tumor metastatic to bone by fine needle aspiration cytology: a case report.

Background: Malignant granular cell tumor (GCT) is a rare sarcoma that is often difficult to differentiate histologically from its benign counterpart.

Case: A 69-year-old Caucasian man with a long history of multiple GCTs presented with new-onset left shoulder pain and limitation of movement. Radiographic studies revealed a lytic lesion within the left humeral metaphysis and a pathologic fracture. Computed tomography-guided fine needle aspiration and needle core biopsies were performed. The patient subse quently underwent curettage of the tumor with prophylactic fixation of the left proximal humerus. He received postsurgical radiation and physical therapy.

Conclusion: The diagnosis of metastatic malignant GCT was rendered in this case. The fne needle aspiration ofmetastatic GCT may lack cytologic features of malignancy. The diagnosis necessitates clinical correlation and an understanding of the spectrum of histopathologic changes in GCT and malignant